fix: remove dedicated ziglang.org mirror as that is not supported by the action

[purpleclay]

closes #24

Summary by CodeRabbit

• Chores
  • Updated the release workflow’s Zig download configuration to use the action’s default mirror selection.
  • Improved workflow comments documenting mirror fallback behavior and download-source restrictions.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: 00771e4e-f979-48b1-9c5b-becedb5393f0

📥 Commits

Reviewing files that changed from the base of the PR and between c54d2e7 and 97c80d8.

📒 Files selected for processing (1)

• .github/workflows/release-rust.yml

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📝 Walkthrough

Walkthrough

The Rust release workflow removes the explicit Zig download mirror override and documents reliance on setup_zig’s default community mirror selection, with ziglang.org retained only as a fallback.

Changes

Rust release mirror configuration

Layer / File(s)	Summary
Use setup_zig default mirrors .github/workflows/release-rust.yml	The setup_zig step no longer sets the ziglang.org mirror and updates comments to describe the action’s default fallback behavior.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related issues

• release-workflows issue 23 — Tracks the immediate setup_zig mirror fix implemented by removing the invalid ziglang.org override.

Possibly related PRs

• purpleclay/release-workflows#2 — Also modifies the shared Rust release workflow’s setup_zig configuration.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: removing the unsupported Zig mirror override.
Linked Issues check	✅ Passed	The workflow change removes the unsupported mirror override and preserves the egress-policy audit setting.
Out of Scope Changes check	✅ Passed	Only the Zig mirror config and related comments were changed; no unrelated scope creep is evident.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch 24-remove-reference-to-ziglang-mirror

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